1. Field of Invention
The invention relates to tires. In particular, the invention relates to enhancing tire traction, such as in wet and/or slippery conditions, for example.
2. Description of Related Art
Traction determines the performance of tires, including those used in a vehicle, such as a car, truck, van, aircraft, motorcycle, bicycle, or ATV, for example. Tire traction is particularly significant since it is the link between the vehicle and the surface on which the vehicle is traveling, such as a road. Aspects of the vehicle performance that are particularly affected by tire traction include vehicle steering, deceleration and acceleration, for example.
Wet and/or icy road conditions may adversely affect tire traction because such conditions change the coefficient of friction between the tire tread and the road surface. Although the coefficient of friction may be adequate to permit acceptable traction for steering, deceleration and/or acceleration in dry conditions for a given tire, the coefficient of friction may drop when the road becomes wet and/or icy. This drop in the coefficient of friction adversely affects tire and vehicle performance.
A significant drop in the coefficient of friction may cause the tire to slip, such as during steering, acceleration, and/or deceleration, and may even cause the tire to hydroplane. Hydroplaning occurs when water becomes disposed between the vehicle tire and the road surface so that the water pressure raises a portion of the tire off of the pavement. As the vehicle speed increases, the water pressure increases to lift a larger and larger portion of the tire off of the road until the tire is only supported by the water. At this point, all contact between the tire and the road surface is lost, which causes the vehicle to lose control.
The speed at which hydroplaning occurs depends on the tire inflation pressure, water depth on the road surface, the condition of the road surface, and/or the condition of the tire tread. A smooth tire may hydroplane on a road surface when contacting a relatively shallow puddle of water. However, even a tire having a well-defined tread pattern may hydroplane when contacting a puddle of water having a depth greater than the depth of the grooves of the tire tread.